(基于文件的) 日志存储

Optuna 提供了 JournalStorage。通过此功能，您可以使用 NFS 作为共享存储轻松地在网络上运行分布式优化，无需设置 RDB 或 Redis。

import logging
import sys

import optuna


# Add stream handler of stdout to show the messages
optuna.logging.get_logger("optuna").addHandler(logging.StreamHandler(sys.stdout))
study_name = "example-study"  # Unique identifier of the study.
file_path = "./optuna_journal_storage.log"
storage = optuna.storages.JournalStorage(
    optuna.storages.journal.JournalFileBackend(file_path),  # NFS path for distributed optimization
)

study = optuna.create_study(study_name=study_name, storage=storage)


def objective(trial):
    x = trial.suggest_float("x", -10, 10)
    return (x - 2) ** 2


study.optimize(objective, n_trials=3)

A new study created in Journal with name: example-study
Trial 0 finished with value: 17.531687176572568 and parameters: {'x': 6.18708576178857}. Best is trial 0 with value: 17.531687176572568.
Trial 1 finished with value: 2.4905531135788244 and parameters: {'x': 3.5781486348182874}. Best is trial 1 with value: 2.4905531135788244.
Trial 2 finished with value: 30.991051799833517 and parameters: {'x': 7.566960732736806}. Best is trial 1 with value: 2.4905531135788244.

尽管本示例中的优化过程很短，不足以并行运行，但您可以扩展此示例来编写可以并行运行的优化脚本。

注意

在 Windows 环境中，可能会出现错误消息“客户端未持有所需的特权”。在这种情况下，您可以通过指定 JournalFileOpenLock 来创建存储以解决此问题。请参阅 JournalStorage 的参考文档了解任何详细信息。